PEX for air compressor lines

anyone here using PEX for running compressed air lines? I don't plan on putting super crazy pressure through the lines, just 120psi or whatever max pressure my air compressor will allow for. I know steel/copper lines are suggested for safety and condensation but I have a ton of PEX left from a job and it's much easier for me to run it in the odd spaces i need to run it in.

I will not use a hard plastic like PVC or CPVC because of their ability to explode and send plastic shrapnel everywhere BUT from what I see, PEX won't explode into shards. As a soft plastic if it would burst I imagine it would split.

Any thoughts? I have done quite a bit of research through google and haven't found any solid information. I'm not worried about the fittings, just if the actual pipe is "safe" and can handle the pressure.

PEX for air compressor lines

Back in the early 90's I worked at a facility that had multiple outlets in two separate buildings all plumbed to one big compressor. The director was a bit of a safety nazi and decided the aging iron & galv. piping had to be replaced before it ruptured. The replacement was a green plastic pipe. I remember being skeptical about this idea at the time. I wonder if it is still in service.

PEX for air compressor lines

Here's a tip and time your running an air manifold use the largest pipe possible.
The pipe acts like an accumulator and and increaces the avalible flow to the tool so it does not start off with full pressure then slow down from lack of air.
Just going from 1/2 to 3/4" increases the flow by about 25%.

PEX for air compressor lines

Pex is not rated for air! it is rated for water PSI of 150 you want the air rating take that 150 and divide it by 3 you get 50 PSI max rating for your air line. Now you know. use stainless steal tubing with nutts and ferrels.

PEX for air compressor lines

Quote:

Originally Posted by Nailbags

Pex is not rated for air! it is rated for water PSI of 150 you want the air rating take that 150 and divide it by 3 you get 50 PSI max rating for your air line. Now you know. use stainless steal tubing with nutts and ferrels.

I thought pressure was pressure?

I do know that a pound of feathers is lighter than a pound of lead though.....

PEX for air compressor lines

@"PoleCat": I also have seen/used the "greenish" colored "plastic" type pipe for compressed air. We ran a lot of this in the mid '80's in our plant. I was skeptical of this at first but it proved to be a quality product. Then just as I was convinced that this was a good product and was useful to us, some contractors came in to run some new fire protection piping using an orange colored "plastic type pipe product". At first thought one may say: "Well, this stuff will surely melt if there is a fire". Yes it will. But by the time the temperature around this pipe gets that hot, the fires too big for the sprinkler system to fight anyway. I currently have my entire shop ran with 1" CPVC piping with four 3/4" drops within the shop. Not one leak since 1996. My training and understanding is that PVC/CPVC will not "explode" if there is a weak spot in the piping. Rather, it will just develop a crack running with the run of the pipe along the piping and allowing air to escape loudly.

PEX for air compressor lines

Seems like there are a lot of opinions that are not specifically backed up with verifiable facts. Couple of points to bear in mind. From the perspective of a pipe, pressure can come from any fluid, whether that fluid be air, water, mercury, or for that matter any liquid or gas. The pipe from a mechanical standpoint behaves exactly the same whether it is subject to 50 psi from air or water, so there is no basis to the claim that 150psi water is the same as 50 psi air.

Certain types of pipe are not rated for specific chemicals. This is a chemical, NOT a mechanical issue. For example, if you want to carry nitric acid, you need glass pipe, because other common types of pipe degrade when in contact with nitric acid. All plastic pipes have temperature ratings, as they typically weaken with rising temperature, hence their pressure rating is temperature dependent. Dry compressed air should not chemically interact with any commonly available plastic pipe.

If a specific PEX manufacturer states that their PEX pipe is not rated for compressed air, that probably means only that the manufacturer has never tested their product for use with compressed air, hence they are not going to warranty it for that particular use. This says nothing about allowable code use. It also says nothing about whether PEX will work acceptably with compressed air, it simply means that manufacturer is not going to warranty their PEX for use with compressed air.

I have found a number of articles claiming that PEX-AL-PEX, which is a particular type of PEX tubing which includes aluminum as an air barrier, is acceptable for use with compressed air. I cannot verify this, however a call to Wirsbo or another manufacturer of this particular type of tubing, commonly used in hydronic heating applications, should confirm if it is OK with compressed air.

The Following User Says Thank You to Daniel Holzman For This Useful Post:

PEX for air compressor lines

Quote:

Originally Posted by joecaption

The pipe acts like an accumulator and and increaces the avalible flow to the tool so it does not start off with full pressure then slow down from lack of air.
Just going from 1/2 to 3/4" increases the flow by about 25%.

You're going to be hard pressed to find air tools outside of an industrial setting that will be limited by a 1/2"pipe. 1/2 " pipe should be good to about 20cfm/100psi for 50' of pipe. Gonna be tough to find an air tool in a home shop that nees even half that.